Incandescent lamp



March 8, 1932. I G PIERSlMON] 1,848,904

TNCANDESCENT LAMP Filed Sept. 2'6, 1930 E'z'avannz Pjarsz'manz' Patented ar. 1932 PATENT OFFICE GIOVANNI PIEBSIMONI, OF AKRON, OHIO INCANDESCENT LAMP Application filed September 26, 1930. Serial No. 484,655.

This invention relates to incandescent lamps and one object of the invention is to provide a lamp having an improved arrangement of lighting filaments in its bulb whereby certain of the filaments may have current passed through them to the exclusion of other filaments, thereby permitting the second set of filaments to constitute reserve filaments intended for use in case the first set of filament-s are burned out.

Another object of the invention is to so arrange the filaments and their lead wires that, while one set of filaments may be employed as reserve filaments and used only when the first filaments have burned out, all of the filaments may be energized at the same time if so desired and thereby increase the power of the lamp.

Another object of the invention is to provide a lamp having such construction that danger of a short circuit will be eliminated and further to so construct the lamp that its base or cap may be engaged in a lamp socket of a conventional construction. Another object of the invention is to permit air in the bulb to be exhausted through a tube extending through the neck of the lamp through which wires for the filaments pass, thereby permitting a vacuum to be formed within the bulb without marring the walls of the bulb. By this arrangement the walls of the bulb will be unbroken and have smooth surfaces.

Another object of the invention is to provide a lamp of this character having a cap or base formed of glass, thereby doing away with a metal base and eliminating any danger of a short circuit.

The invention is illustrated in the accompanying drawings, wherein Figure 1 is a sectional view through the improved lamp,

Fig. 2 is a diagrammatic view of a modified form of lamp,

Fig. 3 is a sectional view illustrating a modified form of base for the lamp,

Fig. 4 is a sectional view illustrating another modified form of base for the lamp, and

Fig. 5 is a sectional view of another modified form of base.

The bulb 1 of this lamp is formed of glass which may be transparent, frosted or colored. Within the bulb is disposed a neck 2 formed I!) of glass and having its outer end portion flared to form a mouth 3, the edges of which are fused to the bulb. A tube 4 extends longitudinally through the neck 2 intermediate the width thereof and this tube is initially open at both its inner and outer ends so that air may be exhausted from the bulb through this tube which projects beyond the outer end of the neck and the projecting end portion of the exhaust tube then heated and pinched together," as shown at 5, to seal the outer end of the tube and prevent air from returning to the bulb through this tube after a vacuum has been established. Other tubes extend through the neck between the exhaust tube and opposite side edge portions'of the neck to receive wires 6, 7 and 8, and by an inspection of Figure 1 it will be seen that, when the neck and tubes are heatedprevious to securing the neck within the bulb, the glass from which the neck and tubes are formed will be fused together, thereby closing the lower ends of the wire receiving passages about the wires and not only preventing any danger of air passing through the wire passages but also causing these wires to be insulated from each other. Filaments 9 connect the inner ends of the wires 6 and 7 and other filaments 10 connect the inner ends of the wires 8 with branch wires 11 leading from the inner end portions of the wires 6. It will thus be seen that current passing inwardly through the wires 6 may pass through the filaments 9 and outwardly through the wires 7 or through the branch wires 11 and filaments 10 and out through the wires 8.

After the neck has been set in place within the bulb and its mouth fused to the walls of the bulb the air is exhausted through the tube 4 and the outer end of this tube then sealed. A cap or base 12 which is also formed of glass for insulating purposes is then filled with aplastic filler 13 and the base fused to the bottom of the bulb about the mouth of the neck.

The lead wires 6 extend through this base 106 i with their outer ends passing through the rear or bottom wall of the base and to the outer ends of these wires are applied contacts 14 which may be dro )s of solder or any other suitable material. Fins 15 extend through side walls of the base and openings 16 are formed through the pins so that the outer end portions of the wires 7 and 8 which project from the base adjacent the rear end of the bulb may be selectively engaged with the pins and firmly secured thereto. Grooves 17 which lead from the bulb to the pins are formed in the side walls of the base in order that the wires which are secured to the pins may be counter-sunk in the base and danger of a short circuit eliminated.

When this improved bulb is in use, the base 12 is fitted into a lamp socket with the pins engaged in slots formed in the walls thereof in the usual manner. The outer end portions of the conductor wires 7 are first secured to the pins and the outer end portions of the wires 8 bent out of the way, as shown in Figure 1, so that they do not have engagement with the pins or the outer ends of the wires 7. When the switch is turned on, the current passes inwardly through the conductor wires 6 to the filament 9 and from these filaments through the wires 7 to the pins, thereby establishing a circuit and causing the filaments to be energized. In case these filaments burn out, the lamp is removed from its socket and the wires 7 are then disconnected from the pins and either broken off or bent out of the way and the wires 8 then extended through the grooves 17 and engaged with the ins. The lamp can then be replaced in its soc et and the filaments 10 will be energized by current passing from the wires 6 through the branch wires 11 and outwardly through the wires 8. It will be readily understood that this eliminates the inconvenience of having a lamp burn out when replacement lamps are lacking. It will also be readily understood that if only one of the filaments 9 burns out only its wire 6 need be disconnected from its pin and the companion wire 8 applied to the pin. It will also be readily seen that, if so desired, the conductor wires may be attached one at a time to the companion pins or that if so desired all of the" conductor wires 7 and 8 may be attached to the pins at the same time, thereby permitting all of the filaments to be energized when a. very bright light is needed.

In Figure 2, there has been shown a modified form of the invention wherein the construction is similar to that shown in Figure 1, except that a single pair of filaments have been provided instead of two sets of filaments. In this form the wire 17, which corresponds to the wires 6, extends longitudinally of the bulb and base with its outer end engaged with a terminal 18, corresponding to the terminals 14, and centrally located upon the base.

There has also been provided wires 19 having their inner ends engaged by filaments 20 and 21, the other ends of which are attached to the wire 17 and to a branch wire 22. These wires 19 project outwardly at the intersection of the base and bulb and one secured to one of the pins while the other is left free. Therefore, either the filament 20 or 21 may be energized and the other serve as a reserve filament. It will be understood that in either form illustrated additional reserve filaments attached to branch wires leading from the wires 6 or 17 may be provided and each attached to return wires 8 or 19 which project outwardly at the intersection of the base and bulb for successive attachment to the pins of the base as the filaments become burned out.

In Figure 3, there has been shown a modified construction. In this embodiment the bulb 1 is formed with an externally threaded shank 23 to the inner end of which the mouth of the tube 2 is fused. Wires 24 and 25, corresponding to the wires 6 and 7', ex tend through the neck and these wires have their outer portions extending into a cap 26 which is internally threaded and is screwed tightly upon the shank 23 after the cap or base has been filled with a plastic filler corresponding to the filler 13. The outer ends of the wires 24 are engaged by terminals 27, corresponding to the terminals 14, and the wires project outwardly through side walls of the base for engagement with pins 28, corresponding to the pins 15.

In Figure 4, the base 29 is molded integral with the bulb 30 and terminates in a conical portion 31 through which ends of the wires 32 and 33 project. These wires which are stiff correspond to the wires 6 and 7 and the wires 32 have their ends projecting straight out of the base near its apex to take the place of the contacts 14 and 27 whereas ends of the wires 33 are bent at right angles to extend radially from the base, as shown at 34, to take the place of the pins 15 and engage in bayonet slots formed in a socket.

In the embodiment illustrated in Figure 5, the bulb has a shank forming portion or extension 35 through which wires 36 and 37 corresponding to the wires 6 and 7, extend and about the extension 35 is disposed a cap or base 38 which may be formed of glass, hard rubber or any other desired insulating material. Contacts 39 and 40 are embedded in openings or sockets 41 formed in the rear wall of the base for engagement by the conductor wires and these contacts are to engage companion contacts provided in a lamp socket of the two-terminal type. A filler 42 of plastic material which hardens when set is provided in the cap or base to firmly hold the same in place about the extension 35 of the bulb and from opposite sides of the cap proj ect pins 43 which take the place of the pins 15 and are to engage in bayonet slots formed in the socket. In the forms shown 1n Figures 4 and 5, the filaments all burn at one time.

5 Having thus described the invention, I

claim:

1. An incandescent multiple filament lamp comprising a bulb, a neck extending into said bulb, a base at the rear end of said bulb, conductor wires extending through the neck and projecting from ends thereof, filaments engaged by inner ends of said wires, and bayonet pins projecting from said base, two of said conductor wires extending through the base and having contacts at their outer ends and the remaining wires projecting externally of the base and releasably engaged with said pins.

2. An incandescent multiple filament lamp comprising a bulb, a neck extending into said bulb, a base at the rear end of said bulb, bayonet pins projecting from sides of the base, terminal contacts carried by said base. conductor wires extending longitudinally of the neck with their inner ends projecting into said bulb, and filaments connected to inner ends of pairs of wires, the outer ends of two of said wires being attached to said contacts and the remaining wires projecting out ofthe base adjacent the bulb and having their projecting portions of suflicient length to extend along the base and bereleasably anchored to the pins.

3. An incandescent multiple filament lamp comprising abulb, a neckextending into said bulb, a base at the rear end of said bulb, bayonet pins projecting from sides of the base, terminal contacts carried by said base, conductor wires extending longitudinally'of the neck with their inner ends projecting into said bulb, and filaments connected to inner ends of pairs of wires, the outer ends of two of said wires being attached to said contacts and the. remaining wires projecting out of the base adjacent the bulb, said base having grooves formed externally in its walls leading from the bulb to said pins and the projecting portions of the last-mentioned wires being adapted to be selectively disposed longitudinally in the grooves and attached to the pins to complete a circuit.

4. An incandescent'multiple filament lamp comprising a bulb, a neck extending into the bulb through the rear end thereof, a base for said bulb enclosing the rear end of said neck,

base and having the remaining wires releasably and selectively engaged therewith.

5. An incandescent multiple filament lamp comprising a bulb, a neck extending into said bulb through the rear end thereof, a base carried by the rear end of said bulb and enclosing the outer end of the neck, a terminal carried by said base, bayonet pins projecting from sides of the base, a conductor for incoming current extending through the neck with its outer end attached to said terminal, conductors for outgoing current extending through said neck with their outer portions projecting from the base and adapted to be selectively attached to one of said pins, a branch leading from the first conductor, and filaments attached to the inner ends of the second conductors and respectively attached to inner ends of the first conductor and its branch.

6. An incandescent multiple filament lamp comprising a bulb, a base for said bulb, contacts carried by said base, bayonet pins projecting from side walls of the base, conductors for incoming current extending into said bulb and having their outer ends extending into the base and attached to the contacts, a branch leading from each conductor into the bulb, a filament attached to each conductor and branch, and conductors for outgoing current extending through said neck with their inner ends attached to said filaments and their outer portions projecting from the base and adapted to be removably secured to said pins whereby the filaments may be selective- 1y energized.

7 An incandescent multiple filament lamp comprising a bulb, a base at the rear end of the bulb, center terminals carried by the base, side terminals carried by the base and constituting pins projecting from sides of the base to serve as bayonet pins for releasably securing the base in a socket, sets of companion conductors having their inner ends extending into the bulb, and filaments bridging inner ends of companion conductors, certain of the conductors having their outer ends anchored to the center terminals and the cooperating conductors having their outer ends selectively engaged with companion terminals whereby the filaments may be individually energized.

In testimony whereof I afiix my signature.

GIOVANNI PIERSIMONI.

a tube extending through said neck whereby air may be exhausted from the bulb, said tube having its outer end closed, conductor wires extending through the neck in insulated relation to each other and having their inner ends projecting into the bulb and connected by filaments terminals for the outer ends of two of said wires carried by said base, and

6 bayonet pins projecting from. sides of the 

